A fiber applied to an optical amplifier, where the fiber includes a rare earth-doped core and a cladding. The core includes a gain equalization unit. The core is configured to separately amplify optical signals of all wavelengths in a received multiplexing wave. The gain equalization unit is configured to equalize gains of the optical signals of all the wavelengths, such that gains of optical signals that are of all the wavelengths and that are transmitted from an egress port of the fiber all fall within a preset range. The gain of the optical signal of each wavelength in the optical signals of all the wavelengths is determined based on a ratio of power of an amplified optical signal to power of the unamplified optical signal.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A fiber comprising: a rare earth-doped core configured to separately amplify optical signals of all wavelengths in a received multiplexing wave; a cladding having a first refractive index that is less than a second refractive index of the rare earth-doped core, wherein the cladding and the rare earth-doped core are sequentially distributed from inside to outside of the fiber; a gain equalizer disposed on the rare earth-doped core and configured to equalize gains of the optical signals of all the wavelengths to generate equalized gains, wherein the equalized gains all fall within a preset range, wherein a start location of the gain equalizer is based on an absorption coefficient and a preset total absorption amount that correspond to a maximum absorption peak in an absorption spectrum of the rare earth-doped core, and wherein gain of each of the optical signals is based on a ratio of power of an amplified optical signal to a power of an unamplified optical signal; and an egress port configured to transmit the optical signals.
2. The fiber of claim 1, wherein the gain equalizer is further configured to perform, based on a total attenuation function of the fiber, energy attenuation on an optical signal corresponding to a gain that is greater than a threshold in the gains of the optical signals of all the wavelengths.
3. The fiber of claim 2, wherein the gain equalizer is further configured to radiate attenuated energy to a direction of the cladding.
4. The fiber of claim 1, wherein the gain equalizer comprises M long period fiber gratings, and wherein M is an integer greater than or equal to 1.
5. The fiber of claim 4, wherein when M is greater than 1, the M long period fiber gratings are dispersedly distributed on the rare earth-doped core from the start location of the gain equalizer.
6. The fiber of claim 4, wherein an attenuation function of each of the M long period fiber gratings is the same as a total attenuation function of the fiber, and wherein a sum of attenuation amplitudes of the M long period fiber gratings is equal to an amplitude of the total attenuation function.
7. An optical amplifier, comprising: at least one stage of an amplification structure comprising: a fiber comprising a rare earth-doped core and a cladding that are sequentially distributed from inside to outside, wherein a first refractive index of the cladding is less than a second refractive index of the rare earth-doped core, wherein the rare earth-doped core comprises a gain equalizer, wherein the rare earth-doped core is configured to separately amplify optical signals of all wavelengths in a received multiplexing wave, wherein the gain equalizer is configured to equalize gains of the optical signals of all the wavelengths to generate equalized gains of optical signals that are of all the wavelengths and that are transmitted from an egress port of the fiber, wherein the equalized gains all fall within a preset range, wherein a start location of the gain equalizer on the rare earth-doped core is based on an absorption coefficient and a preset total absorption amount that correspond to a maximum absorption peak in an absorption spectrum of the rare earth-doped core, and wherein gain of each optical signal of each wavelength in the optical signals is determined based on a ratio of power of an amplified optical signal to power of an unamplified optical signal, a first optical selector configured to receive and transmit optical signals of all wavelengths; a pump source configured to emit pumped light; a multiplexer configured to: receive the optical signals from the first optical selector and the pumped light from the pump source; combine the pumped light and the optical signals into one multiplexing wave; and couple the one multiplexing wave to the fiber; and a second optical selector configured to output, from the fiber, amplified and gain-equalized optical signals that are of all the wavelengths.
8. The optical amplifier of claim 7, wherein the gain equalizer is configured to perform, based on a total attenuation function of the fiber, energy attenuation on an optical signal corresponding to a gain that is greater than a threshold in the gains of the optical signals of all the wavelengths.
9. The optical amplifier of claim 8, wherein the gain equalizer is further configured to radiate attenuated energy to a direction of the cladding.
10. The optical amplifier of claim 7, wherein the gain equalizer comprises M long period fiber gratings, and wherein M is an integer greater than or equal to 1.
11. The optical amplifier of claim 10, wherein when M is greater than 1, the M long period fiber gratings are dispersedly distributed on the rare earth-doped core from the start location of the gain equalizer.
12. The optical amplifier of claim 10, wherein an attenuation function of each of the M long period fiber gratings is the same as a total attenuation function of the fiber, and wherein a sum of attenuation amplitudes of the M long period fiber gratings is equal to an amplitude of the total attenuation function.
13. The optical amplifier of claim 7, wherein the first optical selector and the second optical selector are further configured to isolate reverse propagation of the amplified and gain-equalized optical signals.
14. An optical communications system, comprising: an optical amplifier comprising at least one stage of an amplification structure, wherein the amplification structure comprises: a fiber having a rare earth-doped core and a cladding that are sequentially distributed from inside to outside, wherein a first refractive index of the cladding is less than a second refractive index of the rare earth-doped core, wherein the rare earth-doped core comprises a gain equalizer, wherein the rare earth-doped core is configured to separately amplify optical signals of all wavelengths in a received multiplexing wave, wherein the gain equalizer is configured to equalize gains of the optical signals of all the wavelengths to generate equalized gains of optical signals that are of all the wavelengths and that are transmitted from an egress port of the fiber, wherein the equalized gains all fall within a preset range, wherein a start location of the gain equalizer on the rare earth-doped core is based on an absorption coefficient and a preset total absorption amount that correspond to a maximum absorption peak in an absorption spectrum of the rare earth-doped core, and wherein gain of each optical signal of each wavelength in the optical signals is determined based on a ratio of power of an amplified optical signal to power of an unamplified optical signal; a first optical selector configured to receive and transmit optical signals of all wavelengths; a pump source configured to emit pumped light; a multiplexer configured to: receive the optical signals from the first optical selector and the pumped light from the pump source; combine the pumped light and the optical signals into one multiplexing wave; and couple the one multiplexing wave to the fiber; and a second optical selector configured to output, from the fiber, amplified and gain-equalized optical signals that are of all the wavelengths; a transmitter configured to transmit optical signals of all wavelengths to the optical amplifier; and a receiver configured to receive, from the optical amplifier, amplified and gain-equalized optical signals of all the wavelengths, and convert the amplified and gain-equalized optical signals into electrical signals.
15. The optical communications system of claim 14, wherein the gain equalizer is configured to perform, based on a total attenuation function of the fiber, energy attenuation on an optical signal corresponding to a gain that is greater than a threshold in the gains of the optical signals of all the wavelengths.
16. The optical communications system of claim 15, wherein the gain equalizer is further configured to radiate attenuated energy to a direction of the cladding.
17. The optical communications system of claim 14, wherein the gain equalizer comprises M long period fiber gratings, and wherein M is an integer greater than or equal to 1.
18. The optical communications system of claim 17, wherein when M is greater than 1, the M long period fiber gratings are dispersedly distributed on the rare earth-doped core from the start location of the gain equalizer.
19. The optical communications system of claim 17, wherein an attenuation function of each of the M long period fiber gratings is the same as a total attenuation function of the fiber, and wherein a sum of attenuation amplitudes of the M long period fiber gratings is equal to an amplitude of the total attenuation function.
20. The optical communication system of claim 14, wherein the first optical selector and the second optical selector are further configured to isolate reverse propagation of the amplified and gain-equalized optical signals.
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October 7, 2022
April 1, 2025
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